Electric-arc lamp



(No Model.)

L. H. BUCHANAN. i ELECTRIC ARC LAMP.

No. 447,746. Patented Mar. 3, 1891.

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UNITED STATES PATENT OEEIcE.

LUTHER lI. BUCHANAN, OF PASADENA, ASSIGNOR OF ONE-HALF TO J. DE BARTII SHORE, OF SAN GABRIEL, CALIFORNIA.

ELECTRIC-ARC LAM P.

$PECIFIC'A'1ION forming part of Letters Patent No. 447,746, dated March 8, 1891.

Application filed July 8, 1890. Serial No. 358,039. (No model.)

To all whom it may concern:

Be it known. that l, LUTHER II. BUCHANAN, a citizen of the United States, residing at Pasadena, in the county of Los Angeles and State of California, have invented certain new and useful Improvements in Electric- Arc Lamps, of which the following is a specification.

My invention relates to are lamps, and my improvements include the shape of the carbons, the means for feeding them, and the cut-out.

My object is to produce an arc lamp that will burn a great length of time while still employing but one set of carbons, and which lamp, when burning, will throw n0 obj ectionable shadow. These objects I attain by means of the construction and combination of parts in which my invention consists, as hereinaf- 2o ter described and claimed.

In the accompanying drawings, Figure 1 is a side elevation, partly in section, of my complete lamp. Fig. 2 is a longitudinal section on line 2 2 of Fig. l, a portion of the feed- 2 5 wheel being broken out. Fig. 3 is a detail plan of the carbons; and Fig. i is a detail view of the coils, taken from the side opposite that of Fig. 1 and showing the cut-out connections.

0 In the upper part of a suitable frame X are secured the main and shunt coils A and B, respectively, and to a stud c is pivoted the armature 0, having sides or wings adapted to overlap the cores of the coils alternately,

@ 5 according as it maybe more or less attracted by either of said coils. On each side of the pivot-stud c is a set-screw c to limit the swing of the armature. A downwardly-projecting extension 0 of the armature engages the edge c of the feed-wheel I) when moved in the direction of the arrow, Fig. 1, by the attraction of coil A, and is retracted by a suitable spring a. This feed-wheel is secured to the upper end of the short vertical shaft G, and is pro- 5 vided with an elastic periphery (1, preferably consisting of a round rubber band fitted to a peripheral groove of the wheel. This is to insure a better engagement of the armatureextension with the wheel to rotate it. The

lower end of shaft Gr has a bevel-piniong, which engages a bevel-pinion II, of insulatin g material, which in turn engages with a bevelpinion g on the upper end of a short vertical shaft G". A bracket J, secured to the under side of the frame, has four horizontal 5 5 arms 1, 2, 3, and a of insulating material. The upper shaft G has its bearings in the frame X and arm 1. The pinion II has its horizontal hearings in the arm. 2, and the lower shaft G has its bearings in arms 3 and l. It will thus be seen that the two shafts are thoroughly insulated from each other.

Above the frame X the shaft G has a sleeve F loosely mounted upon but capable of being secured to it by means of set-screw f, and 5 to this sleeve is secured the inner end of a coil-spring E, the other end of which is secured to the frame X at c. The tension of the spring is adjusted by turning the sleeve F on the shaft and securing it by its setscrew, and the spring is so arranged as to have a tendency to turn the wheel D in a direction contrary to that in which it is turned by the armature-extension, and to feed the carbons toward each other, as hereinafter explained.

To the shaft G is secured an arm K, extending out and down and carrying at its end a clip 7t, provided with set-screw 71; for clamping one of the carbons L in said clip, said clip and carbon being below the plane of the lower end of the braeketJ. To the shaft G is secured an arm K, extending out to the same distance from the center of the shaft as the arm K, and carrying at its outer end a clip 7.; having set-screw 7&3 for clamping the other carbon L and carrying it in the same plane with that of the carbon L, carried by arm K. These two carbons, as shown in Fig.

3, when new and placed in the clips form a nearly complete disk or circle, and each forms a sector, one greater and the other less than half the circle. In trimming the lamp the arms K K will be turned back against the action of spring E until nearly or quite in 5 contact with the two sides of bracket J. The carbons will now be secured in the clips, and

the spring will cause their radial edges Z Z to abut against each other.

The positive wire P from the dynamo or I00 other source of electrical energy after passing through the large coil A is connected to at some point between said edges, usually at the center Z and from said starting-point will move back and forth between the edges 1 l, the arc remaining at the point where the two edges approach each other most closely,

and when this point is somewhat consumed moving to the next points which are nearest together. when the edges have been consumed to such. an extent that there'nolonger remainsa point wherethe arc of the proper length can form, the increase of current in shunt-coil B and decrease inmain coil A cause thearmature G to move toward coil 13 and. its extension 0 to leave the wheel D. The spring E now feeds the carbons in the manner above described until the arcisof theproper length,.and the current incoilA causes the extension of the armature to again.

engage the wheel and prevent furtherfeed.

Referring now particularly to Fig, 4, my improved cut-out is to be described as follows: A metallic strip A is secured,,as by screws a, to the insulated'headsof the coils, and. isprovid'edwith curved ends M1), the former being adjacent to but not in contact with the upper side of the projecting end of the iron core of coil A, and the-latter being similarly arranged with respect to but underneath the end ofthe core of coil B. A curved strip a of soft iron is pivoted to the head of coil'A- and extends under its core, and a similar strip 12 issimilarly pivoted with relation to the core of coilB. At their pivotal points these two curved strips have connections a and; 12 respectively, with the wire of the main circuit-one each side of the carbonsand the strip a has a curved spring or thin strip of metal a secured to it and carried over the core and between it and the end a of strip A, and adapted to make contact withv said end a when the pivoted strip a is attracted by the magnet A.

lfhe cut-out operatesas follows: \Vhen the current enters, the lamp and its coils A and B, the two curved strips are attracted to the respective-cores, and the thin spring or strip a makes contact with the end a of strip or bar- A, and as long as there is any current through the lamp remains in thisposition. Atthe same time the curved strip 6 is lifted from the end I) of bar A, and thus prevents short-circuiting through said bar; but if coil B should be brokenor burned out attraction for strip 12 would cease and it would; fall in contact with the end of bar A, and thus out the lamp out, the current flowing through the coil A, connection a strip a spring a, strip or bar A, strip 11 and connection 12 back to the dynamo.

From the foregoing, taken in connection with the accompanying drawings, it will be seen that the construction and arrangement ofmy lamp are such that the vertical dimensions ,are much less than can be had in the ordinary arc lamp in which vertical carbons are employed, and that, consequently, the lamp can be placed in rooms or show-windows havinglow ceilings. The carbons having their contiguous edges Z Z elongated and in substantially-t-he same horizontal plane there are no parts'of the lamp below the arc and no objectionable shadows are cast, and the large amount of carbon thatcan be contained in the disksor sectors is such that the lampcan be used a very long time without trimming.

It is obvious that I may secure one of the carbon sectors against motion and feed the other sectoronly without departing from the principle of my invention.

Having thus described my invention, I- claim- 1. Inan arc l'amp,the combination, withtwosector-shaped carbons, of supporting and carrying arms therefor, one of said arms being pivoted to avsupport, the center of the pivot and. the inner ends of the radii of both sectorsbeing in alignment.

2., Inan arc-lamp, the combination, with two.

sector-shaped carbons, of pivoted supporting and carrying arms therefor, the center of the circle of which the carbons are sectors being in line with the center-0f motion of thearms,

and gearing between the said arms, substantially as described.

3. In an arc lamp, the combinatiomwith .twosector-shaped carbons, of pivoted carr ing-arms therefor, the center of the circle described. by the carbons being in; linewith the center of motionof the arms, gearing'between the said arms, a wheel carried'by thfeshaft of one arm, a magnet and armature for moving said wheel; in one direction, anda spring for moving the shaft and wheel in. the other di-- 'rection, substantially as described 4. In an arc lamp, thecombination, witha pair of carbons, one of which,v is connect-edto an arm carried by a rotary shaft, of a wheel on. said shaft, a: magnet having a portion of its armature engaging the periphery of said wheel, and a spring for rotating said shaft,

substantially as described.

5. In, an arc lamp, the combination, with a.

secured to said shaft and having an elastic periphery, a magnet having its armature engaging said periphery, a sleeve adj ustably secured to the said shaft, and a spring having one end secured to the sleeve and the other end to the frame, substantially as described.

7. In an arc lamp, the combination, with a pair of carbons, one of which is connected to an arm carried by a rotary shaft, of a wheel secured to said shaft, main and shunt magnets in the circuit of the lamp, a pivoted armature having a wing for each magnet and an extension engaging the periphery of the wheel, and an adjusting-screw each side of the pivot of the armature, as described.

8. In an arc lamp, the combination, with the frame, of the bracket J, having insulatingarms 1, 2, 3, and a, a shaft journaled in the lower arms and at and having an arm can rying a carbon, a shaft journaled in the upper arm 1 and the frame and having an arm carrying the other carbon, a bevel-pinion on each shaft, and an intermediate pinion of insulating material meshing with said shaftpinions and journaled in the arm 2 of the bracket, as set forth.

9. A cut-out for are lamps, consisting of main and shunt coils in the circuit, a metallic bar extending from one coil to the other, but insulated therefrom, an armature of the main coil connected to the main circuit and having an extension adapted to make contact with one end of the said bar, and an armature of the shunt-coil connected also to the main circuit and adapted to make contact with the other end of said bar when released by the core of said shunt-coil, substantially as described.

10. The combination, with the coils A and B, of the bar or strip A ,the pivoted strips a and b the former having an extension 0;, and connections from the two pivoted strips to the main circuit, substantially as described.

In witness whereof I have hereunto signed my name in the presence of two subscribing witnesses.

LUTHER IL BUCIIANAX.

Witnesses:

W. O. SWAN, J r., B. Moxxrmn. 

